Manufacture of titanium sulphate solutions



Patented May 39, 1944 uui'rso s'rA'rss PATENT.

v 2,349,936 OFFICE mrmrlic'ruan or mm sunrmrrn sowrrons LBoche G. Bouquet, Wilmington, DeL, David W.

Young, Roselle, N. 1., and Allan W. Low, Woodside, N. Y., assignors to General Chemical (tomnany, New York, N. Y., a corporation of New York c c No ms. Application June 10, 1941,

Serial 180.3973. '11 Claims.

This invention deals withmanufacture of cryssulphate solutions. The invention relates to talloidal-relatively low acidity factor titanium dilution, the sample tested gontainedno colloidal titanium. 1 If analysis of the filtrate or the centrifuge liquor shows appreciably less total titanimethods for reducing acidity factor of crystalloidal titanium sulphate solutions without disparticularly, the invention is directed to methods turbing their crystalloidal characteristics. More for making, from crystalloidal relatively high' acidity factor titanium sulphate solutions. crysthis nature the principal difficulty involved is in carrying out the procedure in such a way as to requiringcareful controlwithin "relatively narthe ratio (multiplied by 100) of the so-called free H2SO4, (i. e., acid not combined with bases or with titanium as 0804) and the titanium equivalent acid based on TiOSOi. (i. e., the acid constituent of TiOSOi as such). Free acid plus acid combined with titanium to form 'IiOSOi as such is designated active acid. a In terminology of the art, zero F. A. represents a condition in which all titanium in solution is present as titanyl sulphate (TiOSOi), and 100% F.- A. represents a condition in which all titanium is present as normal tetravalent titanium disulphate, Ti(SO4)a. Titanium sulphate solution containing less acid than needed to combine with bases other than titanium and to formTiOSOr with the titanium present is designated as having a minus F. A. For example, in a case where solution conditions are such that substantially all of the titanium has been precipitated out as an equal volume of concentrated (-37%) hy= drochloric acid. Should colloidal titanium content of the sample be substantial, coagulated material though'suspended and unsettled'is readily visible to the naked eye. If no coagulated material is visible the hydrochloric acid treated sample may be settled for a substantial period of time and filtered or centrifuged ina highpeed centrifuse. Ifor the filtrate or.

of the centrifuged liquor shows the same total titaniumicalculated as T101) content by weight as didthe sample prior to hydrochloric acid operators.

um than that of the sample prior to hydrochloric acid dilution, it will be evident the sample contained colloidal titanium in amount corresponding' with the total titanium deiiciencyof the filtrate or centrifuge eiliuent subjected toanalysis.

Proposals have been made with respect to methods forreducing the F. A. of crystalloidal titanium sulphate solutions. In operations of avoid formation of colloidal titanium compounds, and with this end in view prior methods have generally involved practice of procedural steps row and also the attention of skilled The principal object of this invention is pro vision ofmethods for reducing acidity factor of crystalloidal titanium sulphate solutions without disturbing their crystalloidal status by procedures the practice of which do not require close chemical control or carefully regulated operating technique. Another important object is to ailord methods for reducing ga'cidity of crystalloidal titanium salt solutions in such a way as to produce crystalloidal salt solutions of very lowrl A., e. g. minus 1 In the production of crystalloidal low F. A. titanium sulphate solutions from crystalloidal high F. A. starting solutions the primarily important features of operation are (a) extraction from the starting solution \of someor all of the socalled free H2804, and in the case of manufacture of products of minus F. A. the extraction of to-form TiOSO4 as such, and (b) in any event the extraction of S04 radical in such a way as to avoid formation of any colloidal titanium compounds. This invention provides for accomplish-- ment of these ends in a simple way. The operating advantages afforded by the present improve-' mehts are based primarily on the discovery of the facility with which certain organic treating agents act on crystalloidal titanium sulphate solution to extract S04 and correspondingly reduce the F. A. of the titanium sulphate solution with respect to titanium sulphate and iron (e. g.

ferrous) sulphate contents. The starting solution is. thoroughly mixed with certain organic treating or extracting agents which, during intimate contact with the starting solution, act to extractortakeupfromthestartingsolution a quantity of the so-called active acid. (31 cessation of agitation and subsequent to a quiescent settling period, the mass stratifles, forming two easily separable liquid layers. The heavier lower layer comprises principally titanium sulphate and iron sulphate, and the F. A. of this layer is -substantiallyless than that of the starting solution. The lighter upper layer comprises a liquid containing chiefly organic extracting agent, sulphuric acid and water. The layers are separated as by decantation. In the more usual practice of the invention, the lower titanium sulphate containing layer is ten diluted with regulated amount or water, and the remlting mass is treated with a second increment of organic ex,- tracting agent. permitted to stratify, and the upper and lower layers separated. The F. A. of

the lower layer. formed by the second extracting operation, is has than the F. A. of the corresponding solution produced in the flrst extraction operation. The series of steps of organic ex- .tracting agent treatment, stratification, separation, and dilution of the heavy titanium sulphate containing layer is carried out once or however manytimesmaybeneededto obtainaflnal titanium sulphate solution having the sought-for from crystalloidal titanium sulphate solutions without disturbing their crystalloidal properties and without permanently contaminating the resulting low F. A. titaniumsulphate product. To a secondary but hardly less important degree the sulphate layer of any one extraction cycle to characteristics similar to those of the startin solution of a preceding extraction cycle.

MnlerelatinggenerallytoRAJeductiomand to manufacture of crystalloidal titanium sulphate solutions having I". A. of zero, the invention is directed particularly to production of crystalloidal solutions having a low minus F. A., preferably not higher than minus 18%. We have -found that to elect acidity reduction of crystalloidal titanium. sulphate, especially to minus quantities, the first feature of importance is that the treatment of the crystalloidal titanium sulphate with the acidity extraction agent should be effected in the presence of appreciable amounts of water. On the basis of our investigations, we' believe that in the presence ofwater some type of hydrolysis forms crystalloidall but weakly bonded sulphuric acid which readily gives up to the extracting agent some of the 804. normally constituting 804 of 110804. The quantity of water in the reaction mas (i. e. the mass formed by mixing the starting solution and the .acid extracting agent) is widely variable, and

S04 removal from T1080; does not seem to depend upon the presence of any critical proporprogressive splitting out of S04 constituent of Minimum and maximum water content of the reaction mass is controlled by two other factors. One procedural step of the instant process comprises the treatment of the titanium sulphate 5 starting solution with the liquid organic extracting agent, which treatment in practice is effected by rapid agitation of a liquid mass consisting of the starting solution and. the extracting agent.

In instances where the water content of the reaction mas is too low, as acid extraction of the titanium-sulphate solution being treated proceeds the mass thickens, and becomes tar-like and unworkable. Hence, the amount of water present during reaction should be such as to 5 avoid this condition and to provide in the mass all during the time of mixing the starting solution and the extracting agent a state of consistency such that the mass may be violently agitated without difliculty. We have also observed that the extracting agents suitable for use in the present process not only extract acid from the titanium sulphate solution but also dehydrate thetitan'ium solution with the result that the should contain suflicient water so that the mass 4 as a whole does not thicken during agitation, and

also so that the lower titanium sulphate layer. after stratification, is fluid enough to be handled as a liquid.

As indicated, another procedural feature of the present process is the carrying out of the extracts ing operation in such a way that after the agitation period, the mass will stratify into a lower layer comprising chiefly titanium. sulphate and ferrous sulphate and into an upper water-extract agent-acid layer. We have found that where the amountof water present in the reaction mass is relatively great, much of the tita- '40 nium salt which would otherwise be held in the invention the discovery of suitable characteristics of the starting solutions, and of the feature of readjustment oi the titaniumlower layer passes into the watery upper layer. Further, in cases of too large amounts of water. no or only very little stratiflcation is obtainedafter completion of the agitating phase, with the result that satisfactory separation of reducedacidity titanium sulphate and the acid carrying extracting agent cannot be secured.

In practice pf theinvention in the more satisfactoryembodiments, a prime feature, aside from prevention of formation of colloidal 'titanium compounds, is the decrease of the acidity factor vto the desired point while effecting economic recovery of titanium in the form of the sought-for low F. A. crystalloidal titanium sulphate soldtion, and at the same time minimizing-titanium loss in the supernatant water-extracting agentsulphuric acid layer formed after treatment of the' starting solution with acidity extracting agent and subsequent to stratification of the reto action products. Attainment of satisfactory titanium recovery makes necessary consideration of certain variable factors whichare' chiefly the 'yvater content of the reaction mass, the titanium and iron concentrations of the starting solution, the ratio of iron to titanium, and the relative quantities of starting solution and acid extracting agent used in any given extracting operation. The importance of the presence and of minimum and maximum quantities of water in the reaction mass is discussed above. Titanium sulphate solutions mosti adaptable for use in practice of the present-process are the clarified, crystalloidal, moderately F. A. (e. g. 50-70%) titanium sulphate solutionswhich are 7 produced by reaction of' ilmenitefandfsulphuric extracting agent takes water away from the 25 titanium sulphate. Hence, the reacticm mass acid and which are well known in the art. Such solutions normally contain substantial amounts of iron almost always in the form of ferrous sulphate. In connection'with the above indicated desirability of carrying out the process in such a way as to secure satisfactory titanium recovery in'the ultimate crystalloidal low 1".A. titanium To secure from the starting solution the desired acidity reduction, satisfactory recovery-oi titanium in the ultimate low F. A. product, and to avoid undesirable titanium loss in the waterextracting agent-sulphuric acid layer formed by stratification, we have found that the three variables just mentioned may 'be accounted for and regulated collectively by providing a crystalloidal titanium sulphate-iron sulphate-water starting solution of suitable F. A. and containing total gpl oi Ti-(calculated as 110804) and of Fe (calculated as FeSO4) not less than 510 and not more than 1100 and having an Fe/TiOz ratio of not less than 0.2 and not more than 0.72. Our work shows that in the better embodiment of the invention process, the presence in the reaction mass 'of some appreciable amount of iron salt, preferably as ferrous sulphate, is desirable, indica tions being that the iron sulphate depresses transfer of titanium salt'into the supernatant water-extracting agent-acid layer. From viewpoint of practicability in making up the starting solutions, the total gpl of Ti and Fe on the one hand and the Fe/TiOa ratio on the other may be readily controlled, and we find. the adjustment of these two factors automatically provides in the reaction mass the desired maximum and minimum concentrations of water and of tita'- nium and iron salts.

To obtain best titanium recovery. and most satisfactory overall operating advantages, it is preferred to use a crystalloidal titanium sulphateiron sulphate-water starting solution containing total gpl of Ti (calculated as 110804) and of Fe (calculated as FeSOdnot less than 5'75 and notmore than 915 and having an Fe/TiOz .ratio of not less'than 0.3 and not more than 0.62. One of the advantages of the invention is that suitable starting solutions may be made by common methods. Starting solutions may be prepared by digesting ground ilm nite with sulphuric acid, clarifying and concentrating the liquor, and

tion, and all of which materials are'neutral orremoving part of the ferrous sulphate by cooling {m and crystallizatiomall as known-in the art. Adjustment of starting solutions to within the above indicated characteristics, with respect to water content, titanium and iron, concentrations, and FelTiO: ratio, may be readily secured by concene trating or water-diluting a clarified titanium sulphate-iron sulphate liquor, or by decreasing (e. g.

by crystallization or by increasing ,the iron sul-.

of 35-30% and possibly lower may be made by direct sulphuric attack on titaniferous ores. However, it is customary in order to obtain satisfactory titanium extraction from ore and to form crystalloidal titanium sulphate solutions which are stable and will not hydrolyze on storage to use acid in quantity to form titanium sulphate solutions having F. A. from above say 5.5 to 100%, general practice 'being such that crude titanium sulphate solutions resulting from ore-acid digestion operations have acidity factors in the range of about -85%. Relatively high F. A. solutions of this general type constitute the commercially more satisfactory starting solutions for making crystalloidal low acidity factor solutions in accordance with the present invention since such high F. A. 'solutions ar e not only crystalloidal but are made in a way affording satisfactory titanium recoveryfrom ore. In practice, however, to insure production of an ultimate low F. A. titanium sulphate solution which is crystalloidal, we prefer to use starting solutions having an F. A. of not below about 40%.

With regard to acid extracting agents, we have discovered that certain organic materials possess acid extracting and other physical and chemical properties of such nature as tamake possible their advantageous use for acidity reduction of crystalloidal titanium sulphate solutions without disturbing the crystalloidal characteristics of such solutions. We find that certain ketones,

alcohols, esters, and others of the following prop-,

'erties and characteristics are suitable for purposesof present process: (1) a neutral organic oxygen containing compound; (2) substantially non-reactive with sulphuric acid at room temperature: (3) soluble in water; and having (4) aspeciflc gravity not above 1.034 at 25 0.; (5) a molecular weight of 46.1 to 118.1 inclusive; (6) a dielectric constant of! to 24.1 inclusive; and (7) a Sugdens Barachor of 126 to 250 inclusive. Following are specific examples of suitable acid ex-' tracting agent falling within the above classificaganic oxygen containing compounds. substantially non-reactive with sulphuric acid at room temperature, and solublein water: i

' Moi. Sp. Sugden's D'elect ic Name weight 25 Parachor constant KETONES A cetone 58. l 793 1 55 gel? lacetone... lgiix 831 :33 u? .f

e ne. 2. 1 80D Di ethyl ketone 86. l 815 g Cyclohexanone- 98. 1 046 About 250 18. 2

ALCOHQLS Ethanol".-. 40.1 .7351 ms l-propanol 60. l 8001 ML 4 pano 00. l 7810 7 165.2 18. 1- tanol 74.1 1805'! 203.9 1 l6. 24111081101- 74. l .8025 200. 4 15. 77

as'rsns Nlctbyl acetate. V 74. 1 .908 117.2 Ethyl acetate 88.1 .886 211.2- :1:

ETHEBS Die thyl -"Celloa e so ya 849 Abo t 2. Ethfl 74. 1 211- 9 i: i-d-dioxaue 88. l l. 084 About 198 nium sulphatesolutions having F. A. of the order n Sugdens parachor is represented by y, Dd

where M is-a molecular weight of the liquid, D is density, '7 its surface tension, and d is the density of the vapor, all measured at the same and alcohols are preferred, and of these groups the more satisfactory results may be obtained by use of acetone, methyl acetone and methyl ethyl ketone on the one hand, and l-propanol, 2-propanol and 1-.butanol on the other. Of the esters, methyl acetate is preferred.

Another feature of importance in'practice of the present process is the relative quantities of starting solution and extracting agent used. To obtain satisfactory results, we treat onepart by volum of starting solution with not less than 0.75 part by volume of extracting agent. In the preferred embodiments, to secure most eflicient acidity reduction, titanium'recovery and economic operation, we employ one volume of starting solution with not less than an equal volume of extracting agent. Although greater amounts of extracting agent may be used, no particular operating advantage arises. 7

Other operating features may be understood from the following general outline of the procedure involved in practice of the improvements constituting the invention. The titanium sulphate starting solution, of the composition and properties noted, is mixed with say one to two parts by volume of the organic acid extracting agent (e. g. acetone) at room temperature in a closed vessel. Use of a closed vessel is preferred to prevent possible vaporization and loss of extracting agent. Another operating advantage is that the extraction process may be carried out at room temperature. No heat is developed by the reaction, and hence there is r o tendency, because. of high temperature cond.-

this connection it is noted that temperatures should always be less than about 60 C. to avoid formation of colloidal titanium.

The mass is agitated to such a degree as to prevent the extracting agent from separating from the titanium solution and forming two separate layers. The .period of mixing and agitation need be only about 10 minutes and not more than about 30 minutes, optimum mixing depending upon the particular operation. The mass is allowed to stratify and the, extracting agent-water-HzSO; mixture separates from the titanium salt solution. Stratification ordinarily requires about 30 minutes.- The lower titanium liquor layer retains some of the extracting agent, but at this stage recovery of the latter is unimporta-nt. The-extracting agent-water-acid-layer is drawn off into a storagetank for further treatment. Water is then added to the titanium sulphate solution which now has an F. A. less than that of the initial starting solution. Primary purpose of adding water is to bring the titanium sulphate solution to a viscosity low enough to permit ready and thorough mixing with another quantityof extracting agent of about the same volume as initially used. Hence, the amount of water added is preferably that sufllcient to bring the titanium sulphate layer back to about the same conditions of fluidity as wasthe starting 1 solution. The quantity of added water may be tions, to form colloidal titanium compounds. In

gauged also by the amount of water needed to bring ,the titanium sulphate layer back to the same TiOz concentration as the starting solution. The readjusted titanium solution is treated again with a second volume of fresh extractin agent asin the previous operation. After stratification and separation, the titanium solution is analyzed to determine whether acid reduction has been carried to th desired point. If not, treatment is repeated until the desired low F. A. is obtained. The resulting basic titanium liquor may be diluted with water to the desired final TiOz concentration and vacuum distilled to vaporize off the small amount of extracting agent held by the titanium solution. It will be under stood that distillation is carried out under conditions of temperature and reduced pressure so as to distill ofi the residual extracting agent without raising the temperature of the titanium solution above 60 C., and in the case of very low F. A. solutions not above 40-50" C. The extracting agent condensate is added to the extracts obtained in the previous steps, and the titanium solution left in the vacuum still constitutes the low F. A. product of the process.

The combined extracting agent-water-acid layers may be distilled in known way to recover the extracting agent in substantially pure form.

Followingare examples of practice of the invention. The crystalloidal relatively high'F. A. starting solutions used were prepared by digesting ground ilmenite with sulphuric acid, clarifying and concentrating the liquor, and removing part of the ferrous sulphate by cooling and crystallization, all as known in the art. Where necessary, the starting solutions were brought to within the previously indicated compositions with regard to water content, Ti and Fe concentrations, and

Fe/T102 ratio, by concentration or dilution with water, or by removal or addition of iron sulphate. In the starting solutions of the examples, it will be understood that minor amounts of impurities are present, but for practical purposes it may be considered that in each case, aside from the constituents listed, the balance of each solution is water.

In these examples 'I'IiOz represents total titanium concentration calculated as TiOz, RTiO:

represents reduced titanium sulphate (titanous sulphate), TH2S04 represents total H2804, FH2SO4 represents free H2804, AH2SO4 represents active H2504, and %v F. A. represents factor of acidity or acidity factor, and mention of TiO: concentration is intended to mean titanium concentration calculated as TlOa.

.nxamm 1 v The crystalloidal titanium sulphate starting solution used analyzed:

In this solution, the total g.p.l. of Ti calcula as 110804 and Fe calculated as F6804 was 592.9. This liquor was extracted three times with three volumes of acetone each equalling the volume oi the starting solution. After each extraction and 1 after each acetone-acid-water layer had been decanted, water' was added to the titanium liquor to reduce viscosity so that the resulting liquor could J column and an adequate water condenser for use in separating residual acetone from the extracted titanium liquor product. Provision was made to carry out this distillation at reduced pressure, and also to cool the acetone-titanium liquor mixture during extraction by circulating water 1269.8 3. in final product Titanium recovery in the product was unnecessarily low on account or use 0! too large a volume of diluting water after the first and second extractions.

Acetone liters Total acetone used i--.. 24 Total acetone recovery 23.43

- Loss 0.57

i lx 100= 97 .59 recovery EXAMPLE II By starting with a higher T10: concentration, and by using less dilution water after each'extraction, the T10: recovery was increased. The starting solution analyzed: 1

through the jacket also used for heating with g g P steam. The three extractions are summarized as 6 follows. Pexce F. A l E -r- In this solution, the total g.p.l. of Ti calculated 1 g- 3 as TIOSOi and Fe calculated as FeSOa was 585.4.

- Volume Ti solutionf -Jitersz. s (o- 30. Extraction No.

Volume acetone.-. ...do.... 8 8 8 li iixingspegd fi P l 508 1 608 l 1 2 3 7 Volume aootonlibh'iitodu -Lii'toisII 9 11 '11s I Volume H10 added do 3. 8 3. 0 3. 2

time to dissolve Tl solution in Volume Tiilquor; c.o 500 Hi0 .--mlnutes-- 5 5 5 Volume 5m 5m 500 Mixing speed .-R. P. M.- 7,500 7,500 7,500 5 5 5 1,500 1,500 1,000 i0 i0 1o 1 Mixed Tl-HIO liquor from IL 625 586 580 I Mixed Ti-HaO liquor from #2. 10g 10g 10g Analysis sits-ass Extitl itts 4mm 1 2 3 4 Acetone hyaoxti-w tinnNo. Volume decanted -.litera-- 0 11 11.5 l tif 53.1" 3. "3 3 '8.% 1 I 3 Total T'i'dJIII. ,401 6 92. 4 109.3 N 4 Ti solution after final extraction and dim 585 580 lotion: .078 .886 .878 i- ------8- P- 5 14 L 57 3. 05 4.45 .81 .51 114 40.0 27.3 ass .98 1.77 i Temperature during the entire extraction op- 6, recov eration did not exceed 50 C. The minus 18.3% F. A. final product was crystalloidal by the herein T1102 1 Ti liquor t -i 05- noted test v Trio: found in acetone 6.33

The final titanium liquor was heatedin the exv r g traction tank at temperature of about 50 C. and 00 .l'IiOz in final titanium pr0duct 100.17 under vacuum of about 26 inches to remove the 1002 I residual acetone and the acetone vapors were X 0= %mcovery condensed. The acetone condensate thus ob- A tained, representing 4.8% of the total. was'added to thethree extracts, and the mixture transferred 11: 1 12:11:53: to the extraction apparatus after the finished low m F. A. titanium product had been. removed. The v acetone was distilled overat the rate of 4 liters 1 z a per hour at B. P. 56-58 C. m I Tio, -ff g m 21 1 217 moi 'I'IiO: 1512' -.'g. in starting solution F g 242.2 g. in extracting agent l 111 In this example an extremely basic titanium liquor was made. Procedure used wasabout the same as in previous examples but more diluting water was added to the titanium solution [between extractions. This gave a lower TiOz recovery, but also a greater acid reduction. The starting solution used was the same as in Example. I.

Extraction No.

Volume Ti liquor .c. c.- 500 500 5L0 Volume acetone c. c. 500 500 500 Mixing time .minlites- 5 5 5 Mixingspeed .R. P. M 1,500 1.500 1,500 Settling time .minutes l0 10 Volume acetone decanted .c. c 595 690 710 Volume H20 added to Ti solutionnnc. c.. 190 240 285 Mixing time to dil. Ti solution. .minutes. 7 3 3 Volume final liquor c. c 520 Analysis Acetone layer extraction 0.

595 690 710 98 I 92 94 8. 5 11. l 20. 4 2. 6 .3. 8 6. l 119. 0 80. 3 54. 0 5. 06 7. 66 I14. 48

Analysis of Ti liquor at each step After extraction No.

500 610 550 TTi0, 181' 148 122 e. 67 53. 6 47. 7 TH;SO4 320 217 166 F. A per cent -8. 92 32. 2 45.0

As shown, the final titanium sulphate product had a minus 45% F. A. Recovery of TiOz was 71.1%-

EXAMPLE IV V 500 c. o Ti starting solutionwas extracted and the total g. p. of Ti calculated as TiOSO4 and Fe calculated as FeSO4 was 674.5.

Atwenty minute period of agitation at 1100 500 c. 0. volume. The analysis of the final product and recoveries were:

25 parts by volume'of starting solution A were extracted twice, each time with 25 parts by volume of 2-buty1 alcohol. In the starting solution, the total g. p. l. of Ti calculated as TiOSO4 and Fe calculated as FeSO4 was 595.3. After thorough agitation the mixture separated into layers. The solvent layer (27 parts by volume) of the first extraction showed the following composition (Soln. B) while the final titanium sulphate prodnot after the second extraction analyzed as shown by Soln. C. I

Solution 190. 5 Nil--- 189. a 5. 6 5. 4 78.8 Nil 78.7 566 as 365.4 195 5. 0 42s 221.2 83.6 2. 15 1.585 .8285 .414 .415

T102 recovery was 99.4%.

EXAMPLE VI parts by volume of starting solution D was extracted twice with (1) 200 parts by volume and (2) 100 parts by volume of methyl ethyl ketone with the following results. In the starting solution, the total g. p. l. of Ti calculated as TiOSO4 and Fe calculated as F6304 was 595.3.

Ti product T-iproduct Solution D after 1st after 2nd 1 extr. extr.

190.5 203 5.6 Present Trace. 78. 8 85 .r 83. 4 566 432.2 387 31.2 i -8.5 478 283.2 210.5 +83.6 +124 -3.4 1.585 413 41 T102 recovery was 98.1%.

In all of the above examples, all of the intermediate and final product solutions were crystalloidal by the hereindescribed test for the absence of colloidal titanium-compound.

We claim:

1. The method for making a crystalloidal titanium sulphate solution of predetermined acidity factor not higher than zero by a plurality of acid extraction operations which method comprises (1) providing a crystalloidal water-titanium sulphate-iron sulphate starting solution of acidity factor not less than 40% and containing total g. p. l. of Ti calculated as Ti0SO4 and Fe calculined as FCSO-i not less than 510 and not more than 1100 andhaving an Fe4/TlOz ratio of not less than 0.2 and not more than 0.72, 2) agitating the starting solution with not less than 0.75 part by volume of a liquid extracting agent comprising a neutral organic oxygen containing compound, substantially non-reactive with sulphuric acid at room temperature, soluble in water, and

having specific gravity not above 1.034 at 25 C.,

a molecular weight of 46.1-118.1, and a dielectric constant of 4-24.1, (3) forming from the mass resulting from step (2) a titanium sulphate solution layer and an extracting agent-acid-water layer, (4) separating said layers, (5) adding to the titanium sulphate solution layer, having acidity factor less than that of said starting solution, water-in amount to form 48mm of viscosity low enough to permit ready mixing with another volume of extracting agent, and (6) subjecting the diluted mass resulting from step (5) to further acid extraction operation comprising repetition of steps (2) to (5) inclusive; the final extraction operation comprising .repetition of steps (2) to (4) inclusive,'and the number-of extraction operations being such as to eflect formation of an and Fe calculated as FeSO4 not less than 575 and not more than 915 and having an Fe/TiOz iatio of not less than 0.3 and not more than 0.62, (2) agitating the starting" solution with not lessthan one part by volume of a liquid extracting agent comprising a neutral organic oxygen containing compound, substantially non-reactive with sulphuric acid at room' temperature, soluble in water, and having specificgravity not above 1.034 at 25 C., a molecular weight of 46.1-118.1, and a dielectric constant of 4-241, (3) forming from the mass resulting from step (2) a titanium sulphate solution layer and an extracting agentacid-water layer, (4) separating said layers, (5) adding to the titanium sulphate solution layer, having acidity factor less than that of said starting solutiomwat'ei' in amount to form a mass of viscosity low .enough to permit. ready mixing with another volume of extracting agent, and (6) subjecting the diluted mass resulting from step (5) tofurther acid extraction'operation comprising repetition of steps (2) to (5) inclusive, the final extraction operation comprising repetition of steps "(2) to (4) inclusive, and the number of extraction operations being such as to effect formation of an ultimate separated titanium sulphate solution layer having said predetermined acidity. factor.

3. The method for making a crystalloidal.

'extracting agent comprising aneutral organic oxygen containing compound, substantially nonreactive with sulfuric acid-at room temperature,

soluble in water, and having a specific gravity not above 1.034 at 25 C.,,a molecular weight of 46.1-118.l, anda dielectric constant of 4-24.1, (3) forming from the mass-resulting from step (2) a titanium sulphate solution layer and an extracting agent-acid-water layer, (4) separating sai'd layers, (5) addingto the titanium sulphate solution layer, having acidity factor less than that of said starting solution, water in amount to form a mass of viscosity low enough to permit ready mixing'with another volume of extracting agent, and (6) subjecting thediluted mass resulting from step (5) to further acid extraction operation comprising repetition of steps (2) to (5) inclusive, the final extraction operation comprising repetition of steps (2) to (4) inclusive, and the number of extraction operations being. such. as to eilect formation of an ultimate separated titanium sulphate solution layer having acidity factor not higher than minus 18%.

4. The method for making a crystalloidaltitanium sulphate solution of predetermined acidity factor not higher than zero by a plurality of acid extraction operations which method comprises (1) providing a crystalloidai water-titanium sulphate-iron sulphate starting solution of acidity factor not less than 40% and containing total g.. p. l. of Ti calculated as T1080; and Fe calculated as F6804 not less than 510 and not more than 1100 and having an Fe/TiOz ratio of not less than 0.2 and not morethan 0.72, (2) agitating the starting solution with not less than 0.75 part by volume of a liquid extracting agent of the group consisting of alcohols, ketones and esters, said agent comprising a neutral organic oxygen, containing compound, substantially .non-

reactive with sulphuric acid at room temperature,

soluble in water, and having specific gravity not above 1.034 at 25 C., a molecular'weight of 46.1-

118.1, and a dielectric constantof 4-241, (3) forming from the mass resulting from step (2) a titanium sulphate solution layer and an extracting agent-acid-water layer, (4) separating said layers, (5) adding to the titaniumsulphate solutionv layer, having acidity factor less than that.

of said starting. solution, water in amount to form amass of viscosity low enough to permit ready mixing with another volume of extract.- ing agent, and (6) subjecting the diluted mass resulting from step (5 to further acid extraction operation comprising repetition of steps (2) to (5) inclusive, the final extrac'tionoperation comprising repetition of steps (2) to (4) inclusive, and the, number of extraction operations being-such as to eflect formation of an ultimate separated titanium sulphate solution layer having said predetermined acidityfactor.

rality of acid extraction operations which method comprises (1) providing a crystalloidal watertitanium sulphate-iron sulphate starting solutionof acidity factor not less than 40% and con- 5. In the method for reducing the acidityfactor of a 'crystalloidal titanium sulphate solution by acid extraction therefrom and without dis- 4 turbing the crystalloidal properties thereof, the steps comprising 1) providing a crystalloidal water-titanium sulphate-iron sulphate starting solution containing total g. p. l. of Ti calculated as TiO SO4 and Fe calculated as'FeSO4 not less than 575 and not more than 915 and having an Fe/TiOz ratio of not less than.0.3 and not'more J than 0.62, (2) agitating the starting solution with not less than one part by volume of a liquid extracting agent comprising a neutral organic Tl oxygen containing compound substantially nonreactive with sulfuric acid at room temperature, soluble in water, and having specific gravity not above 1.034 at 25 (3., a molecular weight of 46.1-

118.1, and a dielectric constant of 4-241, (3)

forming from the mass resulting from step (2) a titanium' sulphate solution layer and an extracting agent-acid-water layer, and (4) sepa rating said layers to recover the titanium sulphate solution layer having acidity factor less than that of said starting solution.

6. The method for making a crystalloidal titanium sulphate solution of predetermined acidity factor not higher than zero by a plurality of acid extraction operations which method comprises 1) providing a crystalloidal water-titanium sulphate-iron sulphate starting solution of acidity factor not less than 40% and containing total g'. p: l. of Ti calculated as T1080; and Fe calculated as FeSOi not less than 5l0'and not more than 1100 and having an Fe/TiOz ratio of not less than 0.2 and not more than 0.72, (2) agi-,

tating the starting solution with not less than 0.75 part by volume of acetone, (3) forming from the mass resulting from step (2) a titanium sulphate solution layer and an acetoneacid-water layer, (4) separating said layers, (5) adding to the titanium sulphate solution layer, having an acidity factor less than that of said starting solution, water in amount to form a mass having a viscosity low enough to permit ready mixing with another volume of acetone, and (6) tanium sulphate solution of predetermined acid-p I ity factor not higher than zero bya plurality of acid extraction operations which method comprises (1) providing a crystalloidal water-titanium sulphate-iron sulphate starting solution of acidity factor not less than 40% and containing total g. p. l. of Ti calculated as T1980; and

Fe calculated as FeSOr not less than 510 and not more than 1100 ,and having an Fe/TiOa ratio of not less than 0.2 and not more than 0.72, (2) agitating the starting solution with not less than 0.75 part by volume of a propanol, (33) forming from the mass resulting from step (2) a titanium sulfate solution layer and a propanol-acid-water .layer, (4) separating said layers, (5) adding to the titanium sulphate solution layer, having an acidity factor less than that of said starting solution, water in amount to form a mass having a viscosity low enough to permit ready mixing with another volume of a propanol, and-(6) subjecting the diluted mass resulting from step (5) to further acid extraction operation comprising repetition of steps (2) to (5) inclusive, the'flnal extraction operation comprising repetition of steps (2) to (4) inclusive only, and the number of extraction operations being such as to efl'ect formation of an ultimate separated titanium sulfate solution layer having said predetermined acidity factor. y

8. In the method for reducing the acidity factoiaof a crystalloidal titanium sulphate solution by acid extraction therefrom and without disturbing the crystalloidal properties thereof, the

water-titanium sulphate-iron sulphate starting solution containing total g. p. l. of Ti calculated as TiOS04 and Fe calculated ajgesm not less than 510 and not more than llofl fltnd having an Fe/TiOz ratio of not less than 0.2' and not more than 0.72, (2) agitating the starting solution with not less than 0.75 by volume of a liquid extracting agent comprising a neutralorganic oxygen containing compound, substantially non-reactive with sulphuric acid at roomtemperature, soluble in water, and having specific gravity not above 1.034 at 25 0., a molecular weight of 46.1-

118.1, and a dielectric constant of 4-241, (3) forming from the massresulting from step, (2) a titanium sulphate solution layer and an extracting agent-acid-w'ater layer, and (4) separating said layersto recover the titanium sulphate solution layer having acidity factor less than that of said starting solution.

9. In the method for reducing the acidity factor of a crystalloidal titanium sulphate solution by acid extraction therefrom and without disturbing the crystalloidal properties thereof, the steps comprising (1) providing a crystalloidal water-titanium sulphate-iron sulphate starting solution containing total g. p. l. of'Ti calculated as 'IiO SOar and Fe "calculated as FeSO; not less than 510 and not more than 1100 and having an Fe/TlOz ratio of not less than 0.2 and not more than 0.72, (2) agitating the starting solution with not less than 0.75 part by volume of a liquid extracting agent of the group consisting of alcohols, ketones and esters, said agent comprising a neutral organic oxygen containing compound substantially non-reactive with sulfuric acid at room temperature, "soluble in water, and having specific gravity not above 1.034 at 25 0., a mo-- lecular weight of 46.1-118.1, and a dielectric constant of 4-241, (3) forming from the mass resulting from:step (2) a titanium sulphate solution 'layer and an extracting agent-acid-waterlayer, and (4) separating said layers to recover the titanium sulphate solution layer having acid-' ity factorless than that of said starting solution 10. In the method for reducing the acidity factor of a crystalloidal titanium sulphate solution by acid extraction therefrom and without disturbing the cry'stalloidal properties thereof, the steps comprising (1) providing a crystalloidal water-titanium sulphate-iron sulphate starting 7 solution containing total 3. p. l. of Ti calculated as H080; and Fe calculated as FeSOr not less than 575 and not more than 915 and having an Fe/TiOz ratio of not less than 0.3 and not more than 0.62, (2) agitating the starting solution with not less than one part by volume of acetone, (3)

1 forming from the mass resulting from step (2) a titanium sulphate solution layer and an acetone-acid-water' layer, and (4) separating said layers to recover the titanium sulphate solution layer having acidity factor less than that of'said starting solution.

, 11. The method for making a crystalloidal titanium sulphate solution of predetermined acidity factor' by a plurality of acid extraction operations which methodoomprises (1) providing ,a crystalloidal water-titanium sulphate-iron sulphate starting solution of acidity factor not less than 40% and containing total. g. p. l. of '11 cal culated as 'IiOSOi and Fe calculated as FeS04 not less than 510 and not more than 1100 and having an Fe/TiOz ratio of not less than 02 and 'not more than 0.72, (2) agitating the starting steps comprising (1) providing a crystalloidal'lli solution with not less than 0.75 part by volume of a liquid extracting agent comprising a neutral organic oxygen containing compound, substantially non-reactive with sulphuric acid at room temperature, soluble in water, and having specific gravity not above 1.034 at 25 0., a molecular weight oi 461-1181, and a dielectric constant of 4-241, (3) forming from the mass resultin from step (2) a titanium sulphate solution layer and an extracting agent-acld-water layer, (4) separating said layers, (5) addin to the titanium sulphate solution layer, having acidity iactor less than that 0! said starting solution, water in amount to mm a mass of viscosity low enough to permit ready mixing with another volume of ing said predetermined acidity iactcr.

n'nocnn a. BOUBQUET. 7 DAVID W.,YOUNG.- ALLAN w. LOW. 

